Biochemical and cytochemical studies of the enzymatic activity of the venom glands of workers of honey bee Apis mellifera L. (Hymenoptera, Apidae)

Biochemical studies revealed that the activity of some hydrolytic enzymes from the venom glands of honey bee Apis mellifera was higher in workers of 14 days of age than in those of 40 days. Among these enzymes, the highest activity was recorded for acid phosphatase, which was cytochemically detected throughout the length of the secretory filament and surrounding the canaliculi of the distal region of the reservoir. The acid phosphatase was considered to be a typical secretion product, since it was present in the cytoplasm as well as in the canaliculi of the secretory cells. (c) 2009 Elsevier Ltd. All rights reserved.

Ultrastructural analysis of the effect of mating delay on cell death in the ovaries of virgin honey bee (Apis mellifera L.) queens

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Surface morphology of Diplodon expansus (Kuster, 1856; Mollusca, Bivalvia, Hyriidae) gill filaments after exposure to environmentally relevant concentrations of atrazine herbicide

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fine structure of Mytella falcata (Bivalvia) gill filaments

Bivalve filter feeders are sessile animals that live in constant contact with water and its pollutants. Their gill is an organ highly exposed to these conditions due to its large surface and its involvement in gas exchanges and feeding. The bivalve Mytella falcata is found in estuaries of Latin America, on the Atlantic as well as the Pacific Coast. It is commonly consumed, and sometimes is the only source of protein of low-income communities. In this study, gill filaments of M. falcata were characterized using histology, histochemistry and transmission electron microscopy for future comparative studies among animals exposed to environmental pollutants. Gill filaments may be divided into abfrontal, intermediate and frontal zones. Filaments are interconnected by ciliary discs. In the center of filaments, haemocytes circulate through a haemolymph vessel internally lined by an endothelium and supported by an acellular connective tissue rich in polysaccharides and collagen. The abfrontal zone contains cuboidal cells, while the intermediate zone consists of a simple squamous epithelium. The frontal zone is composed of five columnar cell types: one absorptive, mainly characterized by the presence of pinocytic vesicles in the apical region of the cell; one secretory, rarely observed and three ciliated with abundant mitochondria. All cells lining the filament exhibit numerous microvilli and seem to absorb substances from the environment. PAS staining was observed in mucous cells in the frontal and abfrontal zones. Bromophenol blue allowed the distinction of haemocytes and detection of a glycoprotein secretion in the secretory cells of the frontal region. The characteristics of M. falcata gill filaments observed in this study were very similar to those of other bivalves, especially other Mytilidae, and are suitable for histopathological studies on the effect of water-soluble pollutants. (C) 2007 Elsevier Ltd. All rights reserved.

Cytoskeletal organization of bee ovarian follicles during oogenesis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Silk formation mechanisms in the larval salivary glands of Apis mellifera (Hymenoptera : Apidae)

The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands were dissected and prepared for light and polarized light microscopy, as well as for scanning and transmission electron microscopy. The results showed that silk formation starts at the middle of the 5th instar and finishes at the end of the same instar. This process begins in the distal secretory portion of the gland, going towards the proximal secretory portion; and from the periphery to the center of the gland lumen. The silk proteins are released from the secretory cells as a homogeneous substance that polymerizes in the lumen to form compact birefringent tactoids. Secondly, the water absorption from the lumen secretion, carried out by secretory and duct cells, promotes aggregation of the tactoids that form a spiral-shape filament with a zigzag pattern. This pattern is also the results of the silk compression in the gland lumen and represents a high concentration of macromolecularly well-oriented silk proteins.

Cytochemical studies of the nuclei of the venom glands' cells of Apis mellifera (Hymenoptera, Apidae)

Cytochemistry studies of the nuclei of the venom glands' cells of worker bees of Apis mellifera indicated that there is a higher activity in the young workers while there is a predominance of degenerative characteristics in the older workers. In addition, we demonstrated that there is an occurrence of differential nuclear synthetic activities between the cells of the distal and the proximal regions of the secretory filament and of the venom reservoir. Signs of a higher nuclear activity were evidenced at the distal regions of this gland in 14-day old workers, while at the more proximal regions of the venom gland of 40-day old workers we identified the most obvious signs of degeneration. Therefore, it was evident that the process of glandular degeneration begins at the distal region of the venom gland instead of beginning at the proximal region as had been established previously. In addition, characteristics of nuclear synthetic activities were noted in the cells of the proximal region of the reservoir; these cells were thought to be non-secretory.

Ultrastructural aspects of the intercellular bridges between female bee germ cells

No ovário das abelhas as células germinativas e as células foliculares são interconectadas por pontes intercelulares mantidas abertas por reforços do citoesqueleto na membrana plasmática. As pontes entre as células germinativas têm comportamento dinâmico e provavelmente atuam na determinação do ovócito entre as células do clone formado pelas mitoses pré meióticas formando posteriormente uma via de transporte para que os produtos sintetizados pelas células nutridoras atinjam o ovócito durante sua maturação. Os elementos do citoesqueleto presentes nas pontes intercelulares das gônadas das abelhas são basicamente microfilamentos e microtúbulos, mas nas pontes entre os cistócitos pré-meióticos outro tipo de filamento (espesso de natureza não definida, associado a elementos do retículo endoplasmático) está presente, atravessando a ponte e prendendo-se através dos microfilamentos à membrana plasmática. Estes filamentos aparentemente controlam o vão da ponte. Terminada a fase de proliferação os cistócitos tomam a forma de uma roseta e um fusoma, formado pela convergência das pontes, aparece no centro desta. Nesta conformação os filamentos grossos não estão presentes. Nova mudança ocorre com a diferenciação do ovócito e das células nutridoras, com a reorientação de todas as pontes de maneira a canalizar o conteúdo das futuras células nutridoras para o ovócito.

Contributions to the floral anatomy of Juncaceae (Poales - Monocotyledons)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Expression of TERT in precancerous gastric lesions compared to gastric cancer

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Exposure to ethinylestradiol during prenatal development and postnatal supplementation with testosterone causes morphophysiological alterations in the prostate of male and female adult gerbils

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Anatomy of smooth muscle cells in nonmalignant and malignant human prostate tissue

Differently graded areas of human prostate adenocarcinoma were examined after Masson's trichrome staining or immunohistochemistry for smooth muscle alpha-actin, type IV collagen and laminin. In addition, the ultrastructure of the prostatic smooth muscle cells (SMC) during glandular proliferation and epithelial invasion in selected tumors was studied. The SMC formed a thick layer below the epithelial structures in unaffected areas and were closely associated with each other in homotypic interactions. As the tumor grade increased, the SMC gradually lost interactions with each other and became atrophic. With the growth of the epithelial compartment, the SMC initially segregated to the tumor periphery and the intercellular spaces increased. In high grade tumors, the epithelial cancer cells invaded the spaces between the SMC. Immunohistochemical analysis of the basal membrane revealed increased disruption of the usually thick basal membrane, which became thinner and faintly stained with each of the antibodies used. We conclude that most SMC become atrophic following epithelial invasion in human tumors and that degradation of the basal membrane is an important factor in this process. At the ultrastructural level, different SMC phenotypes occur in prostatic tissues during epithelial invasion. Interconversion between these phenotypes is suggested and a probable relationship among them is proposed.

Short-term stromal alterations in the rat ventral prostate following alloxan-induced diabetes and the influence of insulin replacement

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

RECK-Mediated Inhibition of Glioma Migration and Invasion

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

High fat-induced obesity associated with insulin-resistance increases FGF-2 content and causes stromal hyperplasia in rat ventral prostate

Obesity affects sex hormone secretion, which can negatively influence prostatic structure, homeostasis, and disease. This investigation aimed to evaluate the repercussions of obesity induced by a high-fat diet on the rat prostate, with or without treatment with the aromatase inhibitor, Letrozole. Adult Wistar rats were fed a high-fat diet (20% saturated fat, O) for 15 weeks to induce obesity or received a balanced diet (4% fat, C). Then, a group of C and O rats were daily treated with Letrozole (1 mg/kg b.w. per day) for 2 weeks (CL and OL, respectively). Subsequently, ventral prostate was processed for analysis by transmission electron microscopy, immunohistochemistry, and Western blotting. Obesity decreased 70% of the testosterone plasma level. The prostate showed epithelial atrophy and dilated acini in the intermediate portion and epithelial wrinkling in the distal tips. The relative frequency of smooth muscle alpha-actin in the O group increased by 67%. Ultrastructurally, epithelial cells in obese animals presented altered secretory organelles, lipid droplets, and thicker subjacent fibromuscular layer. Letrozole treatment caused a partial restoration of the prostatic changes caused by obesity. Obesity increased the prostatic content of fibroblast growth factor-2 (FGF-2) by 150%, and Letrozole treatment increased this protein even more in the control and obese groups. This investigation shows that obesity provokes structural and ultrastructural changes in the epithelium of rat prostate; these changes might affect gland homeostasis and physiology. The epithelial and smooth muscle cell hyperplasia and increased FGF-2 expression observed in this experimental model of obesity/insulin-resistance might explain the high frequency of benign prostatic hyperplasia in insulin-resistant men.